maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/llvm/test/CodeGen/X86/inreg.ll

Ignoring revisions in .git-blame-ignore-revs. Click here to bypass and see the normal blame view.

47 lines
1.2 KiB
LLVM
Raw Normal View History

[FastISel] Disable local value sinking by default This is causing compilation timeouts on code with long sequences of local values and calls (i.e. foo(1); foo(2); foo(3); ...). It turns out that code coverage instrumentation is a great way to create sequences like this, which how our users ran into the issue in practice. Intel has a tool that detects these kinds of non-linear compile time issues, and Andy Kaylor reported it as PR37010. The current sinking code scans the whole basic block once per local value sink, which happens before emitting each call. In theory, local values should only be introduced to be used by instructions between the current flush point and the last flush point, so we should only need to scan those instructions. llvm-svn: 329822
2018-04-12 00:03:07 +08:00
; RUN: llc -fast-isel-sink-local-values < %s -mtriple=i686-pc-linux -mcpu=corei7 | FileCheck --check-prefix=DAG %s
; RUN: llc -fast-isel-sink-local-values < %s -mtriple=i686-pc-linux -mcpu=corei7 -O0 | FileCheck --check-prefix=FAST %s
In order to correctly compile struct s { double x1; float x2; }; __attribute__((regparm(3))) struct s f(int a, int b, int c); void g(void) { f(41, 42, 43); } We need to be able to represent passing the address of s to f (sret) in a register (inreg). Turns out that all that is needed is to not mark them as mutually incompatible. llvm-svn: 160695
2012-07-25 05:40:17 +08:00
When a return struct pointer is passed in registers, the called has nothing to pop. llvm-svn: 160725
2012-07-25 21:41:10 +08:00
%struct.s1 = type { double, float }
In order to correctly compile struct s { double x1; float x2; }; __attribute__((regparm(3))) struct s f(int a, int b, int c); void g(void) { f(41, 42, 43); } We need to be able to represent passing the address of s to f (sret) in a register (inreg). Turns out that all that is needed is to not mark them as mutually incompatible. llvm-svn: 160695
2012-07-25 05:40:17 +08:00
When a return struct pointer is passed in registers, the called has nothing to pop. llvm-svn: 160725
2012-07-25 21:41:10 +08:00
define void @g1() nounwind {
In order to correctly compile struct s { double x1; float x2; }; __attribute__((regparm(3))) struct s f(int a, int b, int c); void g(void) { f(41, 42, 43); } We need to be able to represent passing the address of s to f (sret) in a register (inreg). Turns out that all that is needed is to not mark them as mutually incompatible. llvm-svn: 160695
2012-07-25 05:40:17 +08:00
entry:
When a return struct pointer is passed in registers, the called has nothing to pop. llvm-svn: 160725
2012-07-25 21:41:10 +08:00
%tmp = alloca %struct.s1, align 4
call void @f(%struct.s1* inreg sret %tmp, i32 inreg 41, i32 inreg 42, i32 43)
In order to correctly compile struct s { double x1; float x2; }; __attribute__((regparm(3))) struct s f(int a, int b, int c); void g(void) { f(41, 42, 43); } We need to be able to represent passing the address of s to f (sret) in a register (inreg). Turns out that all that is needed is to not mark them as mutually incompatible. llvm-svn: 160695
2012-07-25 05:40:17 +08:00
ret void
Mass update to CodeGen tests to use CHECK-LABEL for labels corresponding to function definitions for more informative error messages. No functionality change and all updated tests passed locally. This update was done with the following bash script: find test/CodeGen -name "*.ll" | \ while read NAME; do echo "$NAME" if ! grep -q "^; *RUN: *llc.*debug" $NAME; then TEMP=`mktemp -t temp` cp $NAME $TEMP sed -n "s/^define [^@]*@\([A-Za-z0-9_]*\)(.*$/\1/p" < $NAME | \ while read FUNC; do sed -i '' "s/;\(.*\)\([A-Za-z0-9_-]*\):\( *\)$FUNC: *\$/;\1\2-LABEL:\3$FUNC:/g" $TEMP done sed -i '' "s/;\(.*\)-LABEL-LABEL:/;\1-LABEL:/" $TEMP sed -i '' "s/;\(.*\)-NEXT-LABEL:/;\1-NEXT:/" $TEMP sed -i '' "s/;\(.*\)-NOT-LABEL:/;\1-NOT:/" $TEMP sed -i '' "s/;\(.*\)-DAG-LABEL:/;\1-DAG:/" $TEMP mv $TEMP $NAME fi done llvm-svn: 186280
2013-07-14 14:24:09 +08:00
; DAG-LABEL: g1:
When a return struct pointer is passed in registers, the called has nothing to pop. llvm-svn: 160725
2012-07-25 21:41:10 +08:00
; DAG: subl $[[AMT:.*]], %esp
; DAG-NEXT: $43, (%esp)
; DAG-NEXT: leal 16(%esp), %eax
; DAG-NEXT: movl $41, %edx
; DAG-NEXT: movl $42, %ecx
; DAG-NEXT: calll f
; DAG-NEXT: addl $[[AMT]], %esp
; DAG-NEXT: ret
Mass update to CodeGen tests to use CHECK-LABEL for labels corresponding to function definitions for more informative error messages. No functionality change and all updated tests passed locally. This update was done with the following bash script: find test/CodeGen -name "*.ll" | \ while read NAME; do echo "$NAME" if ! grep -q "^; *RUN: *llc.*debug" $NAME; then TEMP=`mktemp -t temp` cp $NAME $TEMP sed -n "s/^define [^@]*@\([A-Za-z0-9_]*\)(.*$/\1/p" < $NAME | \ while read FUNC; do sed -i '' "s/;\(.*\)\([A-Za-z0-9_-]*\):\( *\)$FUNC: *\$/;\1\2-LABEL:\3$FUNC:/g" $TEMP done sed -i '' "s/;\(.*\)-LABEL-LABEL:/;\1-LABEL:/" $TEMP sed -i '' "s/;\(.*\)-NEXT-LABEL:/;\1-NEXT:/" $TEMP sed -i '' "s/;\(.*\)-NOT-LABEL:/;\1-NOT:/" $TEMP sed -i '' "s/;\(.*\)-DAG-LABEL:/;\1-DAG:/" $TEMP mv $TEMP $NAME fi done llvm-svn: 186280
2013-07-14 14:24:09 +08:00
; FAST-LABEL: g1:
When a return struct pointer is passed in registers, the called has nothing to pop. llvm-svn: 160725
2012-07-25 21:41:10 +08:00
; FAST: subl $[[AMT:.*]], %esp
[FastISel] Sink local value materializations to first use Summary: Local values are constants, global addresses, and stack addresses that can't be folded into the instruction that uses them. For example, when storing the address of a global variable into memory, we need to materialize that address into a register. FastISel doesn't want to materialize any given local value more than once, so it generates all local value materialization code at EmitStartPt, which always dominates the current insertion point. This allows it to maintain a map of local value registers, and it knows that the local value area will always dominate the current insertion point. The downside is that local value instructions are always emitted without a source location. This is done to prevent jumpy line tables, but it means that the local value area will be considered part of the previous statement. Consider this C code: call1(); // line 1 ++global; // line 2 ++global; // line 3 call2(&global, &local); // line 4 Today we end up with assembly and line tables like this: .loc 1 1 callq call1 leaq global(%rip), %rdi leaq local(%rsp), %rsi .loc 1 2 addq $1, global(%rip) .loc 1 3 addq $1, global(%rip) .loc 1 4 callq call2 The LEA instructions in the local value area have no source location and are treated as being on line 1. Stepping through the code in a debugger and correlating it with the assembly won't make much sense, because these materializations are only required for line 4. This is actually problematic for the VS debugger "set next statement" feature, which effectively assumes that there are no registers live across statement boundaries. By sinking the local value code into the statement and fixing up the source location, we can make that feature work. This was filed as https://bugs.llvm.org/show_bug.cgi?id=35975 and https://crbug.com/793819. This change is obviously not enough to make this feature work reliably in all cases, but I felt that it was worth doing anyway because it usually generates smaller, more comprehensible -O0 code. I measured a 0.12% regression in code generation time with LLC on the sqlite3 amalgamation, so I think this is worth doing. There are some special cases worth calling out in the commit message: 1. local values materialized for phis 2. local values used by no-op casts 3. dead local value code Local values can be materialized for phis, and this does not show up as a vreg use in MachineRegisterInfo. In this case, if there are no other uses, this patch sinks the value to the first terminator, EH label, or the end of the BB if nothing else exists. Local values may also be used by no-op casts, which adds the register to the RegFixups table. Without reversing the RegFixups map direction, we don't have enough information to sink these instructions. Lastly, if the local value register has no other uses, we can delete it. This comes up when fastisel tries two instruction selection approaches and the first materializes the value but fails and the second succeeds without using the local value. Reviewers: aprantl, dblaikie, qcolombet, MatzeB, vsk, echristo Subscribers: dotdash, chandlerc, hans, sdardis, amccarth, javed.absar, zturner, llvm-commits, hiraditya Differential Revision: https://reviews.llvm.org/D43093 llvm-svn: 327581
2018-03-15 05:54:21 +08:00
; FAST-NEXT: leal 16(%esp), %eax
When a return struct pointer is passed in registers, the called has nothing to pop. llvm-svn: 160725
2012-07-25 21:41:10 +08:00
; FAST-NEXT: movl $41, %edx
; FAST-NEXT: movl $42, %ecx
; FAST: $43, (%esp)
; FAST: calll f
; FAST-NEXT: addl $[[AMT]], %esp
; FAST: ret
In order to correctly compile struct s { double x1; float x2; }; __attribute__((regparm(3))) struct s f(int a, int b, int c); void g(void) { f(41, 42, 43); } We need to be able to represent passing the address of s to f (sret) in a register (inreg). Turns out that all that is needed is to not mark them as mutually incompatible. llvm-svn: 160695
2012-07-25 05:40:17 +08:00
}
When a return struct pointer is passed in registers, the called has nothing to pop. llvm-svn: 160725
2012-07-25 21:41:10 +08:00
declare void @f(%struct.s1* inreg sret, i32 inreg, i32 inreg, i32)
%struct.s2 = type {}
define void @g2(%struct.s2* inreg sret %agg.result) nounwind {
entry:
ret void
; DAG: g2
; DAG-NOT: ret $4
; DAG: .size g2
; FAST: g2
; FAST-NOT: ret $4
; FAST: .size g2
}