[PATCH] D156442: [RISCV][Backend] Zext flag conversion in RISC-V Backend
Panagiotis K via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Mon Aug 28 13:59:34 PDT 2023
karouzakisp updated this revision to Diff 554045.
karouzakisp added a comment.
Herald added a subscriber: sunshaoce.
Added simple tests.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D156442/new/
https://reviews.llvm.org/D156442
Files:
llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp
llvm/test/CodeGen/RISCV/riscv-codegenprepare-asm.ll
llvm/test/CodeGen/RISCV/riscv-codegenprepare.ll
Index: llvm/test/CodeGen/RISCV/riscv-codegenprepare.ll
===================================================================
--- llvm/test/CodeGen/RISCV/riscv-codegenprepare.ll
+++ llvm/test/CodeGen/RISCV/riscv-codegenprepare.ll
@@ -142,3 +142,31 @@
%niter.ncmp.1 = icmp eq i64 %niter.next.1, %unroll_iter
br i1 %niter.ncmp.1, label %for.cond.cleanup.loopexit.unr-lcssa, label %for.body
}
+
+declare void @llvm.assume(i1 %assume);
+define i64 @test3(i32 noundef signext %a){
+; CHECK-LABEL: @test3(
+; CHECK-NEXT: [[ASSUME:%.*]] = icmp sge i32 [[A:%.*]], 0
+; CHECK-NEXT: call void @llvm.assume(i1 [[ASSUME]])
+; CHECK-NEXT: [[EXT:%.*]] = zext i32 [[A]] to i64
+; CHECK-NEXT: ret i64 [[EXT]]
+;
+ %assume = icmp sge i32 %a, 0;
+ call void @llvm.assume(i1 %assume)
+ %ext = zext i32 %a to i64
+ ret i64 %ext
+}
+
+
+define i64 @test4(i32 noundef %a){
+; CHECK-LABEL: @test4(
+; CHECK-NEXT: [[EXT:%.*]] = sext i32 [[A:%.*]] to i64
+; CHECK-NEXT: [[ADDED:%.*]] = add i64 [[EXT]], 5
+; CHECK-NEXT: ret i64 [[EXT]]
+;
+ %ext = zext nneg i32 %a to i64
+ %added = add i64 %ext, 5
+ ret i64 %ext;
+}
+
+
Index: llvm/test/CodeGen/RISCV/riscv-codegenprepare-asm.ll
===================================================================
--- llvm/test/CodeGen/RISCV/riscv-codegenprepare-asm.ll
+++ llvm/test/CodeGen/RISCV/riscv-codegenprepare-asm.ll
@@ -125,3 +125,15 @@
%niter.ncmp.1 = icmp eq i64 %niter.next.1, %unroll_iter
br i1 %niter.ncmp.1, label %for.cond.cleanup.loopexit.unr-lcssa, label %for.body
}
+
+define i64 @test3(i32 noundef %a){
+; CHECK-LABEL: test3:
+; CHECK: # %bb.0:
+; CHECK-NEXT: sext.w a0, a0
+; CHECK-NEXT: addi a0, a0, 5
+; CHECK-NEXT: ret
+
+ %ext = zext nneg i32 %a to i64
+ %added = add i64 %ext, 5
+ ret i64 %added
+}
Index: llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp
+++ llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp
@@ -29,6 +29,8 @@
#define PASS_NAME "RISCV CodeGenPrepare"
STATISTIC(NumZExtToSExt, "Number of SExt instructions converted to ZExt");
+STATISTIC(NumZExtToSExtNonNeg,
+ "Number of SExt non negative value instructions converted to ZExt");
namespace {
@@ -83,7 +85,29 @@
++NumZExtToSExt;
return true;
}
+ // Look for a non negative zext(value) and replace it with sext.
+ if (isKnownNonNegative(Src, *DL)) {
+ auto SExt = new SExtInst(Src, ZExt.getType(), "", &ZExt);
+ SExt->takeName(&ZExt);
+ SExt->setDebugLoc(ZExt.getDebugLoc());
+
+ ZExt.replaceAllUsesWith(SExt);
+ ZExt.eraseFromParent();
+ ++NumZExtToSExtNonNeg;
+ return true;
+ }
+ // Look for zext instructions that have the nneg flag.
+ if (ZExt.hasNonNeg()){
+ auto SExt = new SExtInst(Src, ZExt.getType(), "", &ZExt);
+ SExt->takeName(&ZExt);
+ SExt->setDebugLoc(ZExt.getDebugLoc());
+
+ ZExt.replaceAllUsesWith(SExt);
+ ZExt.eraseFromParent();
+ ++NumZExtToSExtNonNeg;
+ return true;
+ }
// Convert (zext (abs(i32 X, i1 1))) -> (sext (abs(i32 X, i1 1))). If abs of
// INT_MIN is poison, the sign bit is zero.
using namespace PatternMatch;
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